Valve lift adjustment arrangement for a mechanically controllable valve drive arrangement, and method for aligning an intermediate lever arrangement

ABSTRACT

A valve lift adjustment arrangement for a mechanically-controllable valve drive arrangement includes a bearing shaft, a first roller, a second roller arranged on the bearing shaft, a camshaft arrangement, a valve lift adjustment device comprising a rotatable eccentric shaft, an intermediate lever arrangement, and a device. The intermediate lever arrangement comprises an intermediate lever with a working curve. The intermediate lever is mounted via the first roller to be movable in a slotted-guide track and to be operatively connected to the camshaft arrangement and to the valve lift adjustment device. The device is configured so that the second roller is eccentrically mounted. The device comprises a tool engagement point which aligns the second roller and thereby the intermediate lever arrangement. The camshaft arrangement acts, via the first roller, on the intermediate lever arrangement. The rotatable eccentric shaft is acts, via the second roller, on the intermediate lever arrangement.

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C.§371 of International Application No. PCT/EP2012/074306, filed on Dec.4, 2012 and which claims benefit to German Patent Application No. 102012 001 633.6, filed on Jan. 30, 2012. The International Applicationwas published in German on Aug. 8, 2013 as WO 2013/113429 A1 under PCTArticle 21(2).

FIELD

The present invention relates to a valve lift adjustment arrangement fora mechanically-controllable valve drive arrangement of an internalcombustion engine comprising at least one intermediate leverarrangement, wherein the intermediate lever arrangement has at least oneintermediate lever with a working curve, the lever being movablymounted, at least by way of a first roller, in a slotted-guide track andbeing operatively connected to a camshaft arrangement and to a valvelift adjustment device, wherein the camshaft arrangement acts, by way ofa roller, on the intermediate lever arrangement, and wherein the valvelift adjustment device has a rotatable eccentric shaft which acts, byway of a second roller, on the intermediate lever arrangement.

The present invention further relates to a method for aligning anintermediate lever arrangement of the valve lift adjustment arrangement,as well as to a method for assembling a valve lift adjustmentarrangement, i.e., an intermediate lever arrangement, on a pivot leverarrangement.

BACKGROUND

Such arrangements have previously been described in the field ofinternal combustion engines. They specifically serve to adjust thecombustion process to the respective load requirements via valve liftheight, and thus the filling degree of the cylinders of the internalcombustion engine, and to accordingly provide a combustion that is asefficient and thus also as low in emission as possible.

DE 10 2006 033 559 A1 and DE 10 2007 022 266 A1, for example, describevalve drive arrangements with an adjustable lift of a respective gasexchange valve. For this purpose, both valve drive arrangements providean intermediate lever arrangement which is connected to a camshaft inorder to periodically move the gas exchange valve and which comprises anengagement member via which the maximum or minimum possible lift can beadjusted. All these valve drive arrangements have the disadvantage,however, that after manufacture and subsequent assembly, the valve drivearrangements do not have the exactly-desired valve lift due tomanufacturing tolerances. If an exactly-preset valve lift is requiredfor all valves and cylinders, this can result in a dissatisfactoryoperating performance of the engine, particularly for small valve lifts.Reasons therefor can be found in the structure and the cooperation ofthe valve lift adjustment arrangement per se, as well as in the finalassembly of the valve lift adjustment arrangement and the pivot leverarrangement.

An overall structure of an adjustable valve drive arrangement is on thewhole obtained that can be manufactured only with great effort and whichis therefore expensive.

SUMMARY

An aspect of the present invention was provide a valve lift adjustmentarrangement for a mechanically-controllable valve drive arrangement, amethod for aligning an intermediate lever arrangement of the valve liftadjustment arrangement, and a method for the assembly of a valve liftadjustment arrangement which avoids the above-described disadvantages.

In an embodiment, the present invention provides a valve lift adjustmentarrangement for a mechanically-controllable valve drive arrangementwhich includes a bearing shaft, a first roller, a second roller arrangedon the bearing shaft, a camshaft arrangement, a valve lift adjustmentdevice comprising a rotatable eccentric shaft, at least one intermediatelever arrangement, and a device. The at least one intermediate leverarrangement comprises at least one intermediate lever comprising aworking curve. The at least one intermediate lever is mounted, at leastvia the first roller, so as to be movable in a slotted-guide track andto be operatively connected to the camshaft arrangement and to the valvelift adjustment device. The device is configured so that the secondroller is eccentrically mounted. The device comprises a tool engagementpoint configured to align the second roller and thereby the at least oneintermediate lever arrangement so that a circumferential point of thesecond roller, in the case of a rotation through an angle α, describesan arc shape which deviates from a circular arc. The camshaftarrangement is configured to act, via the first roller, on the at leastone intermediate lever arrangement. The rotatable eccentric shaft isconfigured to act, via the second roller, on the at least oneintermediate lever arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in greater detail below on the basisof embodiments and of the drawings in which:

FIG. 1 shows an embodiment of the device of the valve lift adjustmentarrangement according to the present invention;

FIG. 2 shows a perspective view of an embodiment of a distance measuringdevice according to the present invention; and

FIG. 3 shows a sectional view of an intermediate lever arrangement.

DETAILED DESCRIPTION

In an embodiment of the present invention, the second roller, which actson the intermediate lever arrangement through the valve lift adjustmentarrangement, is eccentrically supported on a bearing shaft by way of ameans. A tool engagement point is further provided for a correctalignment of the second roller and thus of the intermediate leverarrangement. When rotated through an angle α, a circumferential point ofthe second roller thereby describes an arc shape deviating from acircular arc. The present configuration of such a valve lift adjustmentarrangement makes it possible to adjust a valve drive arrangement in thepre-assembled state in a simple manner with regard to the correctalignment of the intermediate lever arrangement on the pivot leverarrangement. Manufacturing tolerances or flaws can thus already berecognized before the final assembly and the first operation, and canthereby possibly be compensated or remedied. The simple alignment of themeans fastened eccentrically on the bearing shaft further provides asimple form of aligning in the pre-assembled state.

In an embodiment of the present invention, the means can, for example,comprise an eccentrically-supported bearing shaft. A particularly simpleand economic valve lift adjustment arrangement is thereby provided.

In an embodiment of the present invention, the valve lift adjustmentarrangement can, for example, provide a sleeve. This sleeve is providedon both sides of the bearing shaft and provides the eccentricarrangement of the bearing shaft. This arrangement is an economicvariant. The optimal alignment of the sleeve is performed during theassembly using a special tool. The sleeve has a tool engagement pointfor an optimal alignment.

The means can, for example, be provided in the form of a step. Such astep is provided on both sides of the bearing shaft so that each iseccentric with respect to the bearing shaft, while being arranged withinthe intermediate lever. The steps are different in size so that anassembly can be made from the side, whereas the roller is inserted intothe intermediate lever from the front.

In an embodiment of the present invention, the tool engagement pointcan, for example, be configured as a polygonal connection geometrythrough the sleeve for the eccentric adjustment of the second roller onthe bearing shaft. The tool engagement point can, for example, beconfigured so that the sleeve has a polygonal geometry for engagementwith the tool. This embodiment offers the advantage that the engagementmember can be mass produced in a simple manner. It can, for example, beadvantageous under aspects of assembly and production technology for theengagement member to be integrally formed.

The valve lift adjustment arrangement has reference marks to provide aclear orientation of the valve adjustment arrangement with respect tothe pivot lever arrangement.

These reference marks on the intermediate lever arrangement serve tocooperate with corresponding reference marks of the pivot leverarrangement during a final assembly and thereby provide an optimumalignment.

The present invention further provides a method for aligning anintermediate lever arrangement in a valve lift adjustment arrangement,wherein a distance measuring device with a control unit is providedoutside the valve lift adjustment arrangement. The intermediate lever ismoved relative to the distance measuring device and the working curve isthus traveled along. The measured values obtained by means of thedistance measuring device are compared with reference values in thecontrol unit. If the measured values detected by the distance measuringdevice deviate from the reference values, an adjustment of theintermediate lever arrangement is made via the tool engagement point ofthe sleeve by turning the means or the second roller on the bearingshaft.

In an embodiment, the present invention provides a fixation means sothat, after adjustment, the position of the second roller is fixed bymeans of the fixation means.

Fixation means that act in a form fitting and/or a force locking mannercan be advantageous. These fixation means may be realized, for example,in the form of bolts and/or grooves. It can, for example, beadvantageous under aspects of assembly and manufacturing technology ifthe connection is detachable in the event of a component failure and ifthe defective component can be replaced in a simple manner.

In an embodiment of the present invention, the fixation means can, forexample, be a bonding means, for example, welding or soldering points.Bonding fixation means are advantageous because they represent a simple,secure and stable fixation.

A conventionally used distance measuring devices can be used to detectthe distance between the contour of the working curve of theintermediate lever and the reference values of the pivot leverarrangement. The distance measuring device can, for example, be providedin the form of a capacitive distance sensor, an inductive distancesensor, a measuring sensor with a glass scale, a measuring sensor with aresistance potentiometer, a measuring sensor with inductive detection, ameasuring sensor with LVDT (position sensor) detection, or a measuringdevice based on laser interferometry. Such measuring methods have provento be extraordinarily useful in practice because of their precision.

In an embodiment of the method of the present invention for the assemblyof the valve lift adjustment arrangement, i.e., of an intermediate leverarrangement on a pivot lever arrangement, a match of the reference marksof the intermediate lever arrangement with the reference marks of thepivot lever arrangement is provided. The final assembly of theintermediate lever arrangement and the pivot lever arrangement isperformed after a match of the reference marks has been achieved.

The following is a detailed explanation of the present invention withreference to the drawings.

The following mechanical valve drive is generally known by the name“Univalve”. Reference is made to EP 1 618 293 B1 where the structure andthe functioning of such a valve drive is described.

An embodiment of a valve lift adjustment arrangement 10 for amechanically controllable valve drive arrangement 11 is shown in FIG. 1.The valve lift adjustment arrangement 10 for a piston stroke enginesubstantially comprises an intermediate lever arrangement 12 and a pivotlever arrangement/cam follower arrangement 26. The intermediate leverarrangement 12 comprises an intermediate lever 18 which is slidablysupported in a slotted guide track 13 that is stationarily arranged in acylinder head (not illustrated herein). The shape of the slotted-guidetrack is defined by a circular arc extending around an axial center of athird roller 27. A camshaft arrangement 22 is provided in the region ofthe first roller 14. The camshaft arrangement 22 comprises a camshaft 21which can be displaced directly or indirectly by a first cam 23, therebydriving a gas exchange valve 28. Using the camshaft 21, the gas exchangevalve 28 is opened and closed cyclically if an operative connectionexists between the working curve 24 and the third roller 27 of the camfollower arrangement 26. Alternative embodiments of intermediate leversare of course also covered by the present invention. Two intermediatelevers can thus be arranged on one shaft with one roller, the rollerthen being guided in a slotted-guide track. Reference is thereby made toDE 10 140 635 A1.

A valve lift adjustment arrangement 16 with a second roller 20 isarranged coaxially to the first roller 14 and approximately centrallybetween the slotted-guide track 13 and the working curve 24. The valvelift adjustment arrangement 16 is used to adjust the absolute stroke ofthe gas exchange valve 28 and the opening times of the valve. The valvelift adjustment arrangement 16 comprises an eccentric shaft 17 therefor.

At the end opposite the slotted-guide track 13, the intermediate lever18 comprises the working curve 24 with a zero stroke section, anadjustment stroke section, and a valve lift standstill section.

The intermediate lever 18 is furthermore in an operative connection witha cam follower arrangement 26 via the third roller 27. Various valvelift positions of the gas exchange valve 28 can be controlled via thisoperative connection. The cam follower arrangement 26 is supported on atolerance compensation element, for example, a hydraulic valve tolerancecompensation element, and cooperates with the gas exchange valve 28. Thegas exchange valve 28 and the valve tolerance compensation element aremounted in the cylinder head (not illustrated herein).

FIG. 2 shows a detail of the valve lift adjustment arrangement 10. InFIG. 2, the intermediate lever arrangement 12 is illustrated with thedistance measuring device 32 of the present invention. The distancemeasuring device 32 is arranged below the working curve 24 since theworking curve 24 is to be measured by the distance measuring device 32.

In the shown embodiment, the tool engagement point 36 is integrated inthe sleeve 38 and has two slot-shaped recesses. By turning the sleeve 38through an operation of the tool engagement point 36, the bearing shaftcan be adjusted to a defined rotational position in which it canthereafter be fixed. By simply turning the eccentrically supportedbearing shaft 30 during pre-assembly, it is now possible to adjust thevalve lift of the associated gas exchange valve 28, and in this way, itis possible to detect manufacturing inaccuracies and to perform acorrect alignment of the intermediate lever 18. The shown embodimentprovides for a maximum in flexibility during the adjustment of the valvelift height and the position of the intermediate lever 18. The positionis fixed by a fixation means 37, a welding point 34, in the region ofthe second roller 20 following the correct alignment of the intermediatelever 18.

FIG. 3 illustrates an intermediate lever arrangement 12 with twointermediate levers 18 arranged on a common connecting shaft 40. On theside opposite the working curve 24, first rollers 14 are arranged bywhich the intermediate lever arrangement 12 is operatively connectedwith the camshaft 21. A fourth roller 41 is here arranged on theconnecting shaft 40 between the first rollers 14, which roller serves asa guide roller and rolls in the slotted guide 13 (see FIG. 1). Referenceis made to DE 10 140 635 A1 regarding the function and the operation ofsuch a transmission arrangement. It is noted that an intermediate leverarrangement 12 can have one, as well as two, intermediate levers,wherein, in the embodiment having one intermediate lever, a rollersituated opposite the working curve 24 is operatively connected with thecamshaft 21 and also provides the guiding in the slotted guide 13.

An embodiment of the bearing of the bearing shaft 30 of an intermediatelever 18 is shown wherein the support is achieved with sleeves 38arranged on both sides of the bearing shaft 30. An optimum alignment ofthe sleeves 38 is made by means of a corresponding tool. The sleeves arearranged on the right and on the left of the bearing shaft 30,respectively.

An embodiment differing therefrom, but not illustrated in detail, is astep 39 provided on the right and the left eccentrically with respect tothe bearing shaft 30. This step 39 is supported in the intermediatelever 18. The eccentrically arranged steps 39 may be different in sizeso that an assembly from the side is possible, whereas the roller 20 canbe inserted into the intermediate lever 18 from the front.

The present invention is not limited to embodiments described herein;reference should be had to the appended claims.

What is claimed is: 1-12. (canceled)
 13. A valve lift adjustmentarrangement for a mechanically-controllable valve drive arrangement, thevalve lift adjustment arrangement comprising: a bearing shaft; a firstroller; a second roller arranged on the bearing shaft; a camshaftarrangement; a valve lift adjustment device comprising a rotatableeccentric shaft; at least one intermediate lever arrangement comprisingat least one intermediate lever comprising a working curve, the at leastone intermediate lever being mounted, at least via the first roller, soas to be movable in a slotted-guide track and to be operativelyconnected to the camshaft arrangement and to the valve lift adjustmentdevice; and a device configured so that the second roller iseccentrically-mounted, the device comprising a tool engagement pointconfigured to align the second roller and thereby the at least oneintermediate lever arrangement so that a circumferential point of thesecond roller, in the case of a rotation through an angle α, describesan arc shape which deviates from a circular arc, wherein, the camshaftarrangement is configured to act, via the first roller, on the at leastone intermediate lever arrangement, and the rotatable eccentric shaft isconfigured to act, via the second roller, on the at least oneintermediate lever arrangement.
 14. The valve lift adjustmentarrangement as recited in claim 13, wherein the device further comprisesan eccentrically-supported bearing shaft.
 15. The valve lift adjustmentarrangement as recited in claim 14, further comprising a sleeve arrangedon both sides of the bearing shaft so as to provide an eccentricarrangement thereof.
 16. The valve lift adjustment arrangement asrecited in claim 14, further comprising a step arranged on both sides ofthe bearing shaft so as to be eccentric with respect thereto.
 17. Thevalve lift adjustment arrangement as recited in claim 13, wherein thetool engagement point further comprises a polygonal connection geometry.18. The valve lift adjustment arrangement as recited in claim 13,wherein the valve lift adjustment arrangement comprises reference marksconfigured to provide an orientation with respect to a pivot leverarrangement.
 19. A method for aligning an intermediate lever arrangementof a valve lift adjustment arrangement as recited in claim 13, themethod comprising: providing a distance measuring device comprising acontrol unit comprising reference marks outside the valve liftadjustment arrangement; moving the at least one intermediate leverrelative to the distance measuring device so as to travel along theworking curve so that the distance measuring device obtains a measuredvalue; comparing the measured value with the reference values in thecontrol unit so as to determine if the measured value deviates from thereference values; and adjusting the intermediate lever arrangement viathe tool engagement point by turning the second roller if the measuredvalue deviates from the reference values.
 20. The method as recited inclaim 19, wherein, after the adjusting, the method further comprisesfixing a position of the second roller using a fixation.
 21. The methodas recited in claim 20, wherein the fixation is formed by at least oneof a form-fitting means/device and a force-locking means/device.
 22. Themethod as recited in claim 21, wherein the at least one of aform-fitting means/device and a force-locking means/device is at leastone of a bolt and a groove.
 23. The method as recited in claim 20,wherein the fixation is a bond.
 24. The method as recited in claim 23,wherein the bond is at least one of a welding point or a solderingpoint.
 25. The method as recited in claim 19, wherein the distancemeasuring device is: a capacitive distance sensor, an inductive distancesensor, a measuring sensor comprising a glass scale, a measuring sensorcomprising a resistance potentiometer, a measuring sensor comprising aninductive detection, a measuring sensor comprising an LVDT (positionsensor) detection, or a measuring device based on laser interferometry.26. A method for an assembly of a valve lift adjustment arrangement asrecited in claim 18 to a pivot lever arrangement, the method comprising:providing a valve lift adjusting arrangement as recited in claim 18;providing a pivot lever arrangement comprising reference marks; andmatching the reference marks of the intermediate lever arrangement withthe reference marks of the pivot lever arrangement prior to a finalassembly.